The present invention relates to a device for indicating low compressed air pressure in a tire.
1. Field of the Invention
It is very important to maintain correct tire pressure, or at least to keep the tire pressure above a predetermined minimum acceptable level. This is particularly true for the tire pressure in the tires of heavy-duty road vehicles, such as tractor-trailer rigs. The pressure in these tires is very high, customarily being in the range of from 100-110 psi. This high pressure is necessary in order to keep the tires from running flat, at which point centrifugal forces deform the tire and quickly cause failure thereof. This is, of course, to be avoided, on the one hand for the obvious reason of avoiding accidents, and on the other hand to avoid having to replace the tires, which are very expensive. Thus, for example in connection with such truck tires, there is necessary for the operator of such vehicles to know when the tires of the vehicle have less pressure than that for proper pressure of inflation of the tires; e.g., a readily visible indication is needed to warn when the tire pressure has dropped below a predetermined minimum level, such as 70 psi, and the driver should very quickly locate a service station so that the driver can again inflate or fill the tires to the proper pressure.
2. Description of Prior Art
No practical heretofore disclosed low tire-pressure indicating devices are known to applicant. As a matter of fact, truck drivers presently guess at their tire pressure by thumping the tires with a club, with the resulting sound being the only indication that the tire pressure is not what it should be.
An object of the present invention, therefore, is to provide a device for indicating low tire pressure, which device is not only practical and affordable, but also provides an accurate indication that the tire has or has not dropped below a predetermined minimum level at which more air should be added to the tires.